I think the comments about font lock in meta-mode.el needs some
updating. Here is how it looks now:

;; Font Lock Support:
;;
;; If you are using global-font-lock-mode (introduced in Emacs 19.31),
;; fontification in Metafont and/or MetaPost mode will be activated
;; automatically. To speed up fontification for the rather complex
;; patterns used in these modes, it may be a good idea to activate
;; lazy-lock as a font-lock-support-mode (introduced in Emacs 19.32)
;; by adding these lines to your startup file:
;;
;; (global-font-lock-mode t)
;; (setq font-lock-support-mode 'lazy-lock-mode)